// Copyright 2016 The Draco Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
#ifndef DRACO_IO_OBJ_DECODER_H_
#define DRACO_IO_OBJ_DECODER_H_

#include <string>
#include <unordered_map>

#include "draco/draco_features.h"

#include "draco/core/decoder_buffer.h"
#include "draco/core/status.h"
#include "draco/mesh/mesh.h"

namespace draco {

// Decodes a Wavefront OBJ file into draco::Mesh (or draco::PointCloud if the
// connectivity data is not needed).. This decoder can handle decoding of
// positions, texture coordinates, normals and triangular faces.
// All other geometry properties are ignored.
class ObjDecoder {
  public:
    ObjDecoder();

    // Decodes an obj file stored in the input file.
    // Returns nullptr if the decoding failed.
    Status DecodeFromFile(const std::string &file_name, Mesh *out_mesh);
    Status DecodeFromFile(const std::string &file_name,
                          PointCloud *out_point_cloud);

    Status DecodeFromBuffer(DecoderBuffer *buffer, Mesh *out_mesh);
    Status DecodeFromBuffer(DecoderBuffer *buffer, PointCloud *out_point_cloud);

    // Flag that can be used to turn on/off deduplication of input values.
    // This should be disabled only when we are sure that the input data does not
    // contain any duplicate entries.
    // Default: true
    void set_deduplicate_input_values(bool v) {
        deduplicate_input_values_ = v;
    }
    // Flag for whether using metadata to record other information in the obj
    // file, e.g. material names, object names.
    void set_use_metadata(bool flag) {
        use_metadata_ = flag;
    }

  protected:
    Status DecodeInternal();
    DecoderBuffer *buffer() {
        return &buffer_;
    }

  private:
    // Resets internal counters for attributes and faces.
    void ResetCounters();

    // Parses the next mesh property definition (position, tex coord, normal, or
    // face). If the parsed data is unrecognized, it will be skipped.
    // Returns false when the end of file was reached.
    bool ParseDefinition(Status *status);

    // Attempts to parse definition of position, normal, tex coord, or face
    // respectively.
    // Returns false when the parsed data didn't contain the given definition.
    bool ParseVertexPosition(Status *status);
    bool ParseNormal(Status *status);
    bool ParseTexCoord(Status *status);
    bool ParseFace(Status *status);
    bool ParseMaterialLib(Status *status);
    bool ParseMaterial(Status *status);
    bool ParseObject(Status *status);

    // Parses triplet of position, tex coords and normal indices.
    // Returns false on error.
    bool ParseVertexIndices(std::array<int32_t, 3> *out_indices);

    // Maps specified point index to the parsed vertex indices (triplet of
    // position, texture coordinate, and normal indices) .
    void MapPointToVertexIndices(PointIndex pi,
                                 const std::array<int32_t, 3> &indices);

    // Parses material file definitions from a separate file.
    bool ParseMaterialFile(const std::string &file_name, Status *status);
    bool ParseMaterialFileDefinition(Status *status);

    // If set to true, the parser will count the number of various definitions
    // but it will not parse the actual data or add any new entries to the mesh.
    bool counting_mode_;
    int num_obj_faces_;
    int num_positions_;
    int num_tex_coords_;
    int num_normals_;
    int num_materials_;
    int last_sub_obj_id_;

    int pos_att_id_;
    int tex_att_id_;
    int norm_att_id_;
    int material_att_id_;
    int sub_obj_att_id_;  // Attribute id for storing sub-objects.

    bool deduplicate_input_values_;

    int last_material_id_;
    std::string material_file_name_;

    std::string input_file_name_;

    std::unordered_map<std::string, int> material_name_to_id_;
    std::unordered_map<std::string, int> obj_name_to_id_;

    bool use_metadata_;

    DecoderBuffer buffer_;

    // Data structure that stores the decoded data. |out_point_cloud_| must be
    // always set but |out_mesh_| is optional.
    Mesh *out_mesh_;
    PointCloud *out_point_cloud_;
};

}  // namespace draco

#endif  // DRACO_IO_OBJ_DECODER_H_
